Shugoshin Protein Function in Chromosome Segregation
Figure 1
- a: Cells with Rec8 and Sgo1 alone can grow. When Sgo1 and Rec8 are expressed together, growth is impaired.
- b: A GFP dot marks centromere 2. In cells with Rec8 and Sgo1, the GFP marker migrates to the same side instead of separating, causing nondisjunction.
Nondisjunction: Sister chromatids fail to separate properly. - c: Quantifies nondisjunction seen in Rec8 and Sgo1, which causes a large increase in failed sister chromatid separation.
- d: Rec8-GFP normally disappears during anaphase. When Sgo1
Human Head and Neck Anatomy: Structures and Functions
Concept of the Head
The head is the uppermost part of the body, connected to the neck. It contains the brain, the organs of the senses, and the structures for speech, facial expressions, and chewing.
Parts of the Head and Face
- Head (cabeza): The upper part of the body that contains the brain.
- Hair (cabello): Strands that grow from the scalp.
- Forehead (frente): The flat area between the eyebrows.
- Eyes (ojos): Organs for seeing.
- Iris (iris): The colored part of the eye.
- Pupil: The black circle in the center
Cell Division Mechanics: Mitosis, Meiosis, and Mutations
Introduction to Cell Division
Cell division is the process in which a parent cell (the cell that is the source of other cells) divides into two or more daughter cells (identical cells that form when a cell divides).
Mitosis: The Process of Growth and Repair
Mitosis is a type of cell division where one cell divides into two genetically identical daughter cells. The main purposes of mitosis are to allow for growth, repair, and the reproduction of cells. DNA from the parent cell is replicated so that
Read MoreBiological Organization and Characteristics of Life
Levels of Biological Organization
- Tissue: A group of cells that are connected together.
- Organ: Part of an organism. An organ is a group of tissues that are structured together to perform a certain task in the body.
- Organ System: A biological system that includes a group of organs working together to perform a task.
- Organism: An individual living thing. Can be an animal, plant, fungi, etc.
- Population: A population consists of individuals of the same species. Typically, a population lives in the same area
Human Genetics: Barr Bodies, Karyotyping, and Syndromes
1. Barr Body
Definition
- Barr body is the condensed, inactive X chromosome seen in the nucleus of female somatic cells.
- It is also called sex chromatin.
Formation
- In females (46,XX), one X chromosome becomes inactive.
- The inactive X chromosome becomes highly condensed to form the Barr body.
- X-inactivation occurs early in embryonic development.
Number of Barr Bodies
Formula: Barr bodies = Number of X chromosomes − 1
- Normal female (46,XX): 1 Barr body
- Normal male (46,XY): 0
- Klinefelter (47,XXY): 1
- Turner (45,
Human Health and Disease: Pathogens, Immunity, and Addiction
Common Human Diseases: Pathogens and Symptoms
- Common Diseases (Pathogen | Transmission | Symptoms)
- Typhoid: Salmonella typhi | Contaminated food/water (Widal Test) | High fever, stomach pain, and intestinal perforation.
- Pneumonia: Streptococcus pneumoniae | Droplets/aerosols | Alveoli fill with fluid, grey/blue lips and fingernails.
- Malaria: Plasmodium (vivax/falciparum) | Female Anopheles bite | Chills, high fever every 3-4 days (due to haemozoin toxin).
- Amoebiasis: Entamoeba histolytica | Houseflies